Eight Republicans joined 11 Democrats and narrowly missed killing the bill by substituting a study of prison privatization for the plan itself. The maneuver failed on a 21-19 vote — but one of those voting no was Sen. Dennis Jones, R-Seminole, an ardent opponent of privatization who is eager to sink the entire idea when it's considered Tuesday.

"Let's just kill the bill tomorrow and be done with it," Jones said. "I've been 'No' on the bill from the very beginning."

The only senator from Tampa Bay who favors privatization is freshman Republican Sen. Jim Norman of Tampa.

If no other senator changes his or her vote, privatization appears doomed on a 20-20 tie. Senate President Mike Haridopolos, R-Merritt Island, would not predict the outcome. "I'm not anticipating anything," he said.

Such a close vote is exceedingly unusual in today's Legislature. Republicans have such lopsided majorities in both chambers that they can usually control the outcome, and privatization also is rare in that the outnumbered Democrats may be on the winning side.

With the backing of Gov. Rick Scott, Senate leaders want to privatize 27 prisons and work camps in 18 South Florida counties.

A similar plan, tucked into last year's budget, was struck down as unconstitutional in August by a state judge, so lawmakers are trying again, this time with a stand-alone bill (SB 2038).

The legislation would require vendors to run the prisons for 7 percent less than the state does, a figure that supporters say would save at least $16.5 million in the first year and would have to be verified by an independent state auditor general before vendors were hired.

Sen. John Thrasher, R-St. Augustine, cited a 2010 report by the Legislature's research arm that showed savings of 7.5 to 28 percent at seven existing private prisons in Florida.

Others promoted privatization as a way of staving off deeper cuts to health care and education programs in a no-new-taxes Legislature.

"Sixteen-and-a-half million buys a lot of teachers for the classroom," said Sen. Don Gaetz, R-Niceville.

Opponents insist the project is being rushed through with too little analysis of its broader impact.

"This is a major policy decision, and there's been no analysis done," said Sen. Mike Fasano, R-New Port Richey, who sponsored the amendment to study the privatization plan. While that measure failed, Fasano did succeed in amending the bill to require that private vendors pay the full costs of capturing any escapees.

Another critic, Sen. Paula Dockery, R-Lakeland, said the Senate was ignoring the social costs of privatization, such as the chance that some of the estimated 3,500 officers who would lose their jobs could be forced to turn to food stamps and other public assistance.

Tensions are so high in the Senate that when Haridopolos moved Tuesday's floor session from 9 a.m. to 2 p.m., privatization opponents immediately suspected a backroom maneuver of some kind. Haridopolos said that was untrue.

Word swept through the Capitol that Sen. Jeremy Ring, D-Margate — a no vote — would have to miss Tuesday's session, but his office said Ring would be present.

Two private prison companies, the GEO Group of Boca Raton and Corrections Corp. of America of Nashville, have assembled teams of veteran lobbyists to push the legislation. They have donated more than $2 million to political parties and candidates since 2004, mostly to Republicans.

But the Florida Police Benevolent Association , a union that successfully challenged privatization in court and which until December was the bargaining unit for correctional officers, has spent $2.3 million on candidates and parties during the same period, according to the money-tracking website followthemoney.org.

The Florida Conference of NAACP branches and the Tea Party Network, an umbrella of 80 tea party groups, both came out in opposition to prison privatization Monday. The Tea Party Network's Henry Kelley of Fort Walton Beach said he questioned whether the savings would be realized, and the NAACP said it was dangerous to outsource public safety to a for-profit company.

Times/Herald staff writer Katie Sanders contributed to this report.

HOW THEY VOTED

The Florida Senate voted Monday on an amendment that would have gutted a major prison privatization bill (SB 2038) by replacing it with a study. A yes vote would have effectively killed privatization; a no vote keeps the measure alive. The Senate has 28 Republicans and 12 Democrats.